JP2013119204A - Printing medium having transmission latent image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed article capable of visually recognizing a colorful latent image under transparent light, and visually recognizing different latent images under an IR light source by using a precise dot constitution to a transparent base material.SOLUTION: The printed article is produced by laminating an opacifying layer comprising an opacifying material for suppressing transparent properties on a base material comprising a light transparent material, and furthermore forming an image-forming layer thereon by use of a first region based on a colored coloring material, a second region divided into at least two color divided regions by different colored coloring materials different from each other, and dots in a third region having an IR absorbing coloring element to thereby have a visible image with a continuous gradation, a first full color latent image visually recognized under transparent light and a second visually recognizable latent image under an IR ray light source.

Description

  The present invention is intended for banknotes, passports, securities, product tags, various certificates, and particularly cards such as ID cards, for images under reflected light, images under transmitted light, and images under an infrared light source. The present invention relates to a print medium that is difficult to forge and duplicate by forming three different images.

  In recent years, counterfeit products of valuable printing media such as banknotes, passports, and securities have become a serious problem due to the high functionality and high image quality of copiers. For this reason, various techniques have been developed for valuable print media so that they cannot be reproduced by a copying machine. As one of them, there is a technique for producing a copy prevention effect and a watermark effect under transmitted light by forming an image using a transparent or translucent substrate.

  For example, on one side of a transparent or translucent substrate, a first printing layer, a concealing layer, and a second printing layer are laminated, and an opening that penetrates from the second printing layer to the first printing layer is provided. An anti-counterfeit print medium in which a display unit composed of a dot-like or halftone dot-like pattern is formed is disclosed (for example, see Patent Document 1).

  Since the anti-counterfeit print medium described in Patent Document 1 uses a transparent watermark with an opening other than the pattern exposing the base material, it is difficult to completely reproduce even if a copy is produced using a copying machine. In particular, there is no need for a special authenticity determination device, and since it is possible to easily determine authenticity by visual observation under transmitted light, it has a high discrimination between a genuine product and a duplicate product. In addition, it is possible to use an ink containing a magnetic material added to the printing layer, an ink containing two or more kinds of metallic materials, or a combination of various functional inks. It is possible to achieve a further anti-counterfeit effect.

  Other techniques relating to copying and anti-counterfeiting include the use of functional inks that are difficult to reproduce with copying machines such as color, gloss, or light emission. Functional inks include magnetic inks, fluorescent inks, and infrared absorbing inks that exhibit absorption characteristics in the infrared region. Precious print media using these functional inks are effective for copying on a copier, but for simple characters and designs, if materials are available, they can be forged relatively easily. There is a problem of being able to.

  Therefore, the applicant can not only use the functional ink but also make the visible image and the latent image visible only under specific observation conditions by making a high-definition halftone dot configuration. An anti-counterfeit print medium has been proposed (see, for example, Patent Document 2).

  The anti-counterfeit print medium described in Patent Document 2 is a print medium that forms a gradation image by arranging a plurality of two areas, and the second area is surrounded by the first area. The second region is composed of a region 2a composed of black ink containing an infrared absorbing dye, and a region 2b composed of a black system using ink not containing an infrared absorbing pigment, and the first region and The region 2b uses three primary color inks of cyan (C), magenta (M), and yellow (Y) that are used in general commercial printing.

  Therefore, in addition to the effect of preventing duplication due to a special halftone dot configuration, since a latent image is formed in the area 2a composed of black ink containing an infrared absorbing dye, an infrared camera or the like is identified. When observed with the apparatus, an image that is different from the gradation image observed under a visible light source is completely switched (switched), and has a forgery preventing effect.

  Further, a planar image of three or more layers is formed in the transparent region, and the transparent region is laminated with a transparent substrate sheet provided with the planar image on one side or both sides. An anti-counterfeit carrier made of an absorbing material and an infrared transmitting material is disclosed (for example, see Patent Document 3).

  Since the anti-counterfeit carrier described in Patent Document 3 is a transparent base sheet, it is possible to visually recognize the planar images formed on the laminated layers in a synthesized state. If a discrimination device capable of reading an infrared image is used, only a planar image formed using an infrared absorbing material and an infrared transmitting material can be visually recognized.

  For the techniques disclosed in Patent Documents 2 and 3, it is necessary to use a discrimination device such as an infrared camera, which has a high anti-counterfeit effect, but a discrimination device such as an infrared camera is relatively expensive, Since it was not something that could be purchased by any number of people, it was desired that the above-described technology should be provided with a technology that could be easily discriminated by various window operations.

  Therefore, in addition to the effect of switching between an image under a visible light source and an image under an infrared light source, the applicant of the present invention can view a printed material that is visually recognized by switching another image when the observation angle of the printed material is changed under a visible light source. (For example, refer to Patent Document 4).

  The printed matter of Patent Document 4 uses a glittering material as a base material, and a concealing layer for suppressing the glittering property is provided on the base material. Further, a visible image and an infrared light source are visible on the concealing layer. By forming a printed layer for forming a latent image that can be formed, and hollowing out the same portion of the printed layer and the concealing layer or providing a region with a low concealment ratio, the glittering property of the substrate is exhibited, and the observation angle is set. This is a technique for visualizing another latent image by making it different.

Japanese Patent Application Laid-Open No. 10-76745 Japanese Patent No. 3544536 JP 2006-68987 A JP 2010-247515 A

  However, since the print medium described in Patent Document 1 has a transparent watermark formed by having an opening penetrating from the second print layer to the first print layer, a transparent watermark is formed under transmitted light. Although it is possible to easily determine authenticity by visual recognition, the transparent watermark by the opening is a simple pattern, and if the layer structure is known, it can be counterfeited and imitated relatively easily. There was a problem that.

  In addition, since the transparent watermark by the opening is a simple pattern and does not form a design having a continuous tone, it is desired to form a design rich in design. At the same time, the transmission latent image is also of a single color depending on the color of the transmitted light and has a poor color feeling.

  Furthermore, when visually recognizing a transparent watermark under transmitted light, the pattern and visible information formed on the second print layer are also viewed together, and cannot be viewed as individual images. Therefore, a more advanced anti-counterfeiting technology has been demanded.

  The halftone dot printing medium described in Patent Document 2 has two images: a visible image that can be recognized under a visible light source by a special halftone dot configuration, and a latent image that can be visually recognized using a discrimination device such as an infrared camera. Has been achieved at low cost. However, since the latent image is not visually recognized unless a discrimination device such as an infrared camera is used, for example, inspectors in various window operations such as banks and immigration examinations should make a true / false discrimination by simple visual inspection. There was a problem that could not be. Accordingly, there is a need for a forgery-preventing print medium that is provided with a technique that can be used to visually determine the authenticity without using a special determination device, in addition to the appraisal authenticity determination using a special determination device.

  In addition, the anti-counterfeit carrier described in Patent Document 3 is formed by laminating a transparent base sheet and forming a planar image on each layer, so that each planar image formed on each layer is synthesized. Since the viewing state of the planar image of each layer can be changed by tilting the viewing angle, it is possible to discriminate by visual observation, and at least one planar image is formed. The layer is formed using an infrared absorbing material and an infrared transmitting material. Therefore, by using a discriminating device that can read an infrared image, appraisal authenticity discrimination can also be performed, and both a visual discrimination and an appraisal discrimination using a discriminating device are provided. Since the planar image formed on the sheet has a simple pattern, if the layer configuration is known, it may be forged relatively easily.

  In addition, for an infrared image visually recognized under an infrared light source, a plane image of one layer may be formed using an infrared absorbing material and an infrared transmitting material. Because it has a problem that the same image will be formed if even the material can be obtained, even if a material with special functionality can be obtained, There has been a demand for a print medium with higher security that has a configuration in which the same image or the like cannot be easily formed.

  In addition, the printed matter disclosed in Patent Document 2 and Patent Document 3 in which the problem that the latent image in Patent Document 1 is limited to a design with a small number of gradations can be determined by a simple inspection such as visual inspection. There was a problem that it was not possible. Furthermore, the printed matter disclosed in Patent Document 4 in which these problems are solved is based on the color of the base material or the color (single color) of the printing layer for forming the latent image, and has various color latents. There has been a demand for an improvement that allows an image to be visually recognized.

  The purpose of the present invention is to solve such a conventional problem. By using a dense halftone dot structure, it is difficult to replicate, and even a transparent base material, which is a special base material, is provided. It is possible to visually recognize a clear first latent image with a color feeling under transmitted light, and under a special observation condition such as under an infrared light source, the visible image and the first latent image An object of the present invention is to propose a print medium capable of visually recognizing a second latent image different from the image.

  In the present invention, a transparent latent image region is formed on a part of a substrate made of a light transmissive material, and the transmission latent image region on the substrate is formed of at least a part of the substrate made of a colorless and / or colored light transmissive material. In the image area, a concealing layer made of a concealing material for suppressing the transmittance of the light transmissive material, and an image forming layer formed of a color material on the concealing layer are formed. The first concealment region for concealing the transparency of the substrate and the second concealment region, wherein the second concealment region includes the concealment portion of the second a to which the concealment material is applied and the hollow portion without the concealment material. Or a concealment area ratio of the first concealment region, the second concealment unit, and the second concealment unit is expressed as follows: 1 hiding area ≧ 2a hiding part> 2b hiding part, and the image forming layer is at least The first region has a first halftone dot portion that forms a visible image with a colored color material, and the second region is mutually connected. Divided into at least two color separation regions by different colored color materials and laminated at the same position as the second concealment region, the second region is a hollow portion or the second b concealment portion. A latent image portion that hits the same position and a first camouflage portion that hits the same position as the second-a concealing portion are divided into a plurality of latent image portions to form a first latent image, and the second region In this case, the latent image portion and the first camouflage portion are formed so as to have the same color under the reflected light (diffused light), so that a visible image is visually recognized under the reflected light (diffused light) and the latent image portion under the transmitted light. The color difference ΔE between the image portion and the first camouflage portion changes by a predetermined value A print medium having a transparent latent image of the first latent image formed by the latent image portion is equal to or visible.

  Further, the printing medium having a transmission latent image of the present invention is characterized in that the latent image portion is formed with a light transmittance (hereinafter referred to as “transmittance”) of 3% to 100%.

  In the printing medium having a transmission latent image according to the present invention, at least two color separation regions have different colors depending on the color material of cyan, magenta, yellow, black, or a special color for each color separation region. It is characterized by being formed.

  In the printing medium having a transmission latent image according to the present invention, the second area is divided into three color separation areas, and each color separation area is formed of colored materials of cyan, magenta, and yellow, or The second area is divided into four color separation areas, and each color separation area is formed of colored materials of cyan, magenta, yellow, and black.

  Further, the print medium having the transmission latent image of the present invention is different in the size of the latent image portion by changing the size of the plurality of cutout portions or the second b concealing portions, The latent image is a gradation image.

  The print medium having a transmission latent image according to the present invention is characterized in that a cutout portion or a second-b concealment portion having a different size is formed corresponding to at least two color separation regions.

  Furthermore, the print medium having the transmission latent image of the present invention is formed in the first region or the second region so as to surround the third halftone dot portion and the third halftone dot portion. The third region is formed of a camouflage portion, and the third halftone dot portion is formed of a colored color material containing an infrared absorbing dye, thereby forming a second latent image, and the second camouflage. The portion is formed of a color material that is the same color as the third halftone dot portion under a visible light source and does not include an infrared absorbing dye, and at least the first region does not include an infrared absorbing dye, When the latent image area is observed under an infrared light source, the second latent image is further visible.

  The print medium having a transmission latent image of the present invention has a gradation visible image when viewed in a diffused light region under a visible light source, and the print medium is observed in full color or multiple colors by observing the print medium under transmitted light. The color latent image can be visually recognized, and authenticity determination can be performed by a simple method. Further, by further providing a region using an infrared absorbing material, it is possible to perform authenticity determination using a special appraisal device.

  In the printing medium having a transmission latent image of the present invention, a fine region for forming a first full-color latent image that is visible when the printing medium is observed under transmission light has yellow (hereinafter referred to as “yellow”). “Y”), cyan (hereinafter referred to as “C”), magenta (hereinafter referred to as “M”) and black (hereinafter referred to as “Bk”) are formed as regions corresponding to a full color image to be formed. Therefore, since the fine structure requires advanced design technology, the anti-counterfeit resistance is further improved.

It is a figure which shows an example of the printing medium which has the transmission latent image image in this invention. It is a figure which shows an example of the visible image and 1st latent image in this invention. It is a figure for demonstrating the layer structure of a transmission latent image area | region. It is a figure for demonstrating the concealment layer in 1st Embodiment. It is a figure for demonstrating the image forming layer in 1st Embodiment. It is a figure for demonstrating arrangement | positioning of a 2nd area | region and a 2nd concealment area | region. It is a figure for demonstrating the layer structure of the three layers in 1st Embodiment. It is a figure for demonstrating the structure of the concealment layer and image formation layer of the 1st aspect in 1st Embodiment. It is a figure for demonstrating the structure of the concealing layer and image formation layer of the 2nd aspect in 1st Embodiment. It is a figure for demonstrating the observation state when observing the printing medium of this invention. It is a figure for demonstrating color difference (DELTA) E of the latent image part and camouflage part under the reflected light and transmitted light in connection with this invention. It is a figure for demonstrating the principle when a visible image is visually recognized. It is a figure for demonstrating the principle when a 1st latent image is visually recognized. It is a figure for demonstrating the concealment layer in 2nd Embodiment. It is a figure which shows the visible image, 1st latent image, and 2nd latent image in 3rd Embodiment. FIG. 10 is a diagram for describing images formed by three regions in an image forming layer in the third embodiment. It is a figure for demonstrating the layer structure of the three layers in 3rd Embodiment. It is a graph which shows an example of the spectral transmittance of white ink and magenta ink. It is a figure for demonstrating the spectral reflectance in 3rd Embodiment. It is a figure at the time of observing the printing medium using the base material containing an infrared rays absorption dye under an infrared light source. It is a figure at the time of observing the printing medium using the base material which does not contain an infrared absorption pigment | dye under an infrared light source. It is a figure for demonstrating the modification of the shape of a 1st area | region and a 2nd area | region. It is a figure explaining the certificate of Example 2. FIG. It is a figure which shows the visible image in Example 2, a 1st latent image, and a 2nd latent image. 6 is a diagram for explaining a layer configuration of three layers in Example 2. FIG.

  Embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments to be described below, and includes various other embodiments within the scope of the technical idea described in the claims.

  FIG. 1 is a diagram showing an example of a print medium (1) (hereinafter referred to as “print medium”) having a transmission latent image in the present invention. As shown in FIG. 1A, the print medium (1) has a transmission latent image region (2) in which a transmission latent image according to the present invention is formed at least partially.

  In this print medium (1), a visible image (3) as shown in FIG. 2A is visually recognized under reflected light (diffused light) under a visible light source, and FIG. 2 under transmitted light under a visible light source. As a result, the first latent image (4) as shown in (b) can be visually recognized. The principle of visual recognition of these two images will be described later.

  The transmission latent image region (2) is composed of three layers as shown in FIG. 1 (b) which is a cross-sectional view of the print medium (1). The transmission latent image region (2) may be formed on a part of the print medium (1) as shown in FIG. 1, but the entire surface of the print medium (1) is formed as the transmission latent image region (2). May be. The three layers constituting the transmission latent image region (2) are formed of the base material (6), the concealing layer (7), and the image forming layer (8). These three layers will be described next.

(First embodiment)
First, the substrate (6) will be described. The base material (6) is formed using a light-transmitting material (5) that is at least partially colorless and / or colored. The transmittance of the light transmissive material is preferably in the range of 3% to 100%. As the colorless (transparent) transparent base material, there is a transparent film formed of a material such as PET or vinyl chloride. In addition, as the colored transparent base material, there are those obtained by adding coloring components such as dyes and pigments to the above-mentioned colorless (transparent) PET film and the like, and transparent colored inks and colored films are laminated. May be formed.

  Further, a transparent metallic glossy film (manufactured by Toray Industries, Inc., PICASUS, etc.) may be used for the substrate (6). The metallic glossy film is a polyester film formed by laminating different kinds of polymers and is a light-transmitting material capable of obtaining a metallic gloss without using a metal.

  In FIG. 1 (b), the entire surface of the print medium (1), that is, the base material itself is formed of the light-transmitting material (5), but the base material (6) of the present invention is formed with this. However, the substrate (6) may be partially formed of the light transmissive material (5).

  For example, as shown in FIG. 3, the light transmissive material (5) may be formed only in a portion corresponding to the transmission latent image region (2).

  Next, the hiding layer (7) will be described. The masking layer (7) plays a role of suppressing the permeability of the base material (6) that hits the lower layer. Further, the concealing layer (7) needs to have a color that does not affect the visible image (3) formed by the upper image forming layer (8) described later. Therefore, although the concealing layer (7) can use white ink, mat ink (mat type OP varnish), etc., it is a concealing material capable of suppressing the lower layer transparency, and the upper layer visible image (3). The material is not particularly limited as long as it does not affect the material. In the present embodiment, description will be made by forming using white ink. The white ink includes Dicure RTX white manufactured by DIC Corporation as UV ink for offset printing, and LIOJET FV03 white manufactured by Toyo Ink Manufacturing Co., Ltd. as UV ink for inkjet printing. In the present invention, ink for ink jet printing is defined as “ink”, and ink for other printing is defined as “ink”.

  As shown in FIG. 4, the concealing layer (7) has a cutout portion (9) where a concealing material is not applied in part. The configuration of the concealing layer (7) shown in FIG. 4A corresponds to the halftone dot configuration of the image forming layer (8) described later. This halftone dot configuration is a fine halftone dot configuration used in the present invention, and details will be described in the description of the image forming layer (8).

  FIG. 4A is a schematic diagram in which a part of the concealing layer (7) is enlarged, but the concealing layer (7) is formed from two regions so as to correspond to an image forming layer (8) described later. Has been. Since these two regions have a role of concealing the transparency of the base material (6) as the lower layer as described above, the first concealment region (10) and the second concealment region (11). It consists of Moreover, the 2nd concealment area | region (11) is comprised by the 2a concealment part (12) to which the concealment material is given, and the hollow part (9) to which no concealment material is given.

  Here, the concealment area ratio is a ratio of an area for forming a concealment material per unit area of the first concealment region (10) or the 2a concealment portion (12) in the concealment layer (7). For example, in the 2a concealing part (12), the concealed area ratio of 80% means that the ratio of the area where the concealing material is formed is 80% of the area of the 2a concealing part (12). In this case, 20% of the area of the 2a concealing portion (12) is in a state where the underlying base material (6) is exposed because no concealing material is formed.

  Therefore, lowering the hidden area ratio of the second-a concealing portion (12) than the first hidden area (10) means that the exposed area ratio of the base material (6) as the lower layer is lowered by lowering the hidden area ratio. And the lowering of the transparency of the second-a concealing portion (12) is suppressed more than the first concealing region (10). That is, when the print medium (1) is changed from under reflected light (diffused light) to under transmitted light, the first region (13) of the image forming layer (8) corresponding to the first concealment region (10). ), The intensity of light per unit area of the transmitted light of the first camouflage portion (16) of the image forming layer (8) corresponding to the concealment portion (12) of the 2a is higher than the transmitted light of This is because the visibility of the first latent image (4) under transmitted light may be improved.

  However, by reducing the concealed area ratio, the intensity of the transmitted light of the hollow portion (9), that is, the transmitted light of the base material (6) and the transmitted light of the second concealed region (11) is approximated. The visibility of the first latent image (4) below may also be reduced. Therefore, the hidden area ratio of the second hidden region (11) needs to be set as appropriate.

  Further, as described above, the second concealment region (11) has a hollow portion (9), and is an (enlarged) cross-sectional view taken along line X1-X2 in FIG. 4 (a). As shown in FIG. 3, white ink is not applied to the cut-out portion (9). Next, the cut-out portion (9) will be described with reference to FIGS. 4 (c) and 4 (d).

  As shown in FIG. 4C, the second concealment region (11) includes a cutout portion (9) and a 2a concealment portion (12). In FIG. 4C, the edge of the cut-out portion (9) is represented by a dotted line to show the second concealment region (11), but this line does not actually exist.

  As shown in FIG. 4D, the cutout portion (9) includes at least two cutout portions (9) corresponding to a second region (14) of an upper image forming layer (8) described later. . When there are two hollow portions (9), they are defined as a hollow portion (9a) and a hollow portion (9b). When there are three hollow portions (9), a hollow portion (9c) is further added. . The details of the second region (14) of the image forming layer (8) will be described in detail when the image forming layer (8) is described. However, the second region (14) Since the original image of the latent image (4) is divided by the color material of at least two of the color components obtained by color separation, three cutout portions (9a) are divided for each divided region of the color components. 9b and 9c). FIG. 4D shows a case where the second region (14) of the image forming layer (8) is composed of color materials of three color components, and three of the second regions (14). In order to show that it corresponds to a region divided into two color components, for the sake of explanation, it is represented using dotted lines in the figure, but in reality, the second concealment region (11) has two Or it is not divided into three.

  Regarding the size of the three cutout portions (9a, 9b and 9c) in FIG. 4D, which is the size of the cutout portion (9) in FIG. 4C, an image forming layer (8) described later will be described. Are appropriately set in accordance with the gradation of the first latent image (4) formed using the second region (14). This is the same concept as that in which gradation is expressed by the size of halftone dots when a gradation image is formed using ordinary halftone dots.

  By forming the hollow portion (9) in the second concealing region (11), when the print medium (1) is observed under transmitted light, the transmitted light from the transparent base material (6) is cut out. Through (9), the first latent image (4) formed in the second region (14) of the uppermost image forming layer (8) can be viewed. Details of this observation principle will be described later.

  Next, the image forming layer (8) will be described. The image forming layer (8) forms a visible image (3) including a continuous tone image visible under reflected light (diffused light) under a visible light source by halftone dots. Therefore, the halftone dot configuration of the image forming layer (8) will be described with reference to FIG.

  The image forming layer (8) forms the visible image (3) shown in FIG. 5 (a), and the halftone dot configuration is a configuration partially shown in FIG. 5 (b). This halftone dot structure is formed by a first region (13) and a second region (14), and a plurality of first regions (13) and a plurality of second regions (14) are arranged in a matrix. By arranging these two regions in a matrix, the visible image (3) and the first latent image (4) do not generate moire.

  As shown in FIG. 5B, the second region (14) is disposed so as to be surrounded by the first region (13), and the second region (14) is more than the first region (13). Are arranged at equal intervals along the outer periphery of the first region (13) with a small area. When the second region (14) is formed with an area larger than that of the first region (13), the second region (14) becomes noise and the visible image (3) is viewed under a visible light source. It will reduce the nature. The details of this halftone dot configuration are disclosed in Japanese Patent No. 3544536 filed by the present applicant.

  A first halftone dot portion (13a) is arranged in the first region (13), and the visible image (3) is connected to the first halftone dot portion (13a) in the first region (13). A plurality of first regions (13) arranged according to the area ratio with the region other than the first halftone dot portion (13a) can provide gradation.

  The second area (14) is an area for forming a first latent image (4) that is visible when the print medium (1) is observed under transmitted light. In order to make (4) visible, the transmittance of the second region (14) needs to be in the range of 3% to 100%. The second area (14) includes at least two color separation areas in which the original image of the first latent image (4) to be formed is formed from YMCK or a special color material. For example, when there are two color separation regions, they are defined as a 2a region (14a) and a 2b region (14b), and when there are three color separation regions, a 2c region (14c) is further added. Made up. Thereafter, the number corresponds to the number of color division regions. Note that where the YMCK or spot color material is formed in the disassembled second region (14) may be appropriately set, and is not particularly limited.

  When the second region (14) is divided into at least two color separation regions, each color separation region is divided by being formed with different colors. At this time, each color separation region may be formed by a single color of YMCK, but may also be formed by a special color material produced by mixing a plurality of color materials. Even if a plurality of color materials are mixed, this special color material is formed of one special color material when one color separation region is formed. Further, when a single color material based on YMCK process basic components is used, one color separation region may be formed of only a single color material, but two or more color materials may be printed in an overlapping manner. In any case, as described above, the color material forming the color separation area in the present invention is formed in different colors using the color material of the basic component of YMCK and the special color material. It is sufficient if it is divided by.

  There are two modes in the second region (14). First, the first mode will be described. Hereinafter, since the second area (14) is composed of three color separation areas of YMC, the 2a area (14a), the 2b area (14b), and the 2c area (14c). It will be explained by comprising.

  The second region (14) is formed in the same region on the lower second concealment region (11) described above, and the second concealment region (11) is a hollow portion where no concealing material is applied. (9) and the second-a concealing portion (12) to which the concealing material is applied, so that the transmissive material (5) (the base (6) itself is formed from the light transmissive material (5). In the case where the light is transmitted, the light is divided into a portion that directly receives the transmitted light from the transparent base material (6) and a portion where the transmitted light is suppressed by the concealing material. The first latent image (4) formed by the difference in the transmitted light of the divided transparent substrate (6) has an area ratio between the hollowed out part (9) and the second concealing part (12). Accordingly, gradation can be given by the plurality of second regions (14) arranged.

  Although the three color separation regions of YMC constituting the second region (14) have been described, this arrangement may be divided in the direction shown in FIG. As shown to b), you may divide | segment in the direction rotated 90 degree | times with respect to Fig.6 (a). Furthermore, in the 2nd area | region (14) arrange | positioned in multiple numbers, you may divide | segment in a respectively different direction, and it is not specifically limited.

  As described above, the second concealment region (11) formed in the lower layer of the second region (14) has a hollow portion (9) (in particular, a hollow portion (9a), a hollow portion (9b), and Since the cutout portion (9c) corresponds to the YMC dividing the second region (14), when the second region (14) is arranged as shown in FIG. When the cutout portion is arranged in the second concealment region (11) as shown in FIG. 6C, and when the second region (14) is arranged as shown in FIG. 6B, FIG. This is the arrangement of the cut-out portions in the second concealment region (11) as shown in d).

  Here, the principle that the first latent image (4) is formed by the second region (14) will be described in more detail with reference to FIG.

  FIG. 7A shows a base material (6) and a concealing layer (when a pair of the first region (13) and the second region (14) arranged in FIG. 5 is taken out. 7) is a perspective view illustrating a stacked state of the image forming layer (8), and FIG. 7B is a cross-sectional view taken along line Y1-Y2 of FIG.

  As shown in FIGS. 7A and 7B, the first concealment region (10) of the concealment layer (7) and the first region (13) of the image forming layer (8) are arranged at the same position. Similarly, the second concealment region (11) and the second region (14) are stacked at the same position. Further, the three color separation areas constituting the second area (14) of the image forming layer (8) are the 2a area (14a), the 2b area (14b), and the 2c area (14c). ), The three cutout portions (9a, 9b and 9c) of the second concealment region (11) are at the same position. Therefore, as shown in FIG. 7 (b), the second region (14) laminated on the cutout portion (9) is (the second region (in FIG. 14b)), since there is no concealing material, it is substantially in a state of being laminated on the substrate (6).

  In FIG. 7, the layer structure of the three layers has been described. However, as described above, the hollow portion (9) of the concealing layer (7) is not provided with the concealing material. The second region (14) of the image forming layer (8) is substantially formed thereon. Here, since the base material (6) is formed of a transmissive material, it transmits the irradiation light from the light source. Therefore, the portion corresponding to the second region (14) above the cut-out portion (9) not provided with the concealing material for suppressing the transmitted light is the basis when the print medium (1) is observed under the transmitted light. By being provided with the concealing material, the region affected by the transmitted light of the material (6) is divided into a region not affected by the transmitted light of the base material (6). This state is shown in FIG.

  FIG. 8A shows the second concealment region (11) of the concealment layer (7) and the second region (14) of the image forming layer (8) among the three layers described in FIG. It is the perspective view which decomposed | disassembled the lamination | stacking state. In this state, FIGS. 8B and 8C show cases where the respective regions are viewed from directly above. Note that the second region (14) in FIG. 8B is a state when the print medium (1) is observed in the diffused light region, and the second region (14) is constituted by three color separation regions. Has been. Actually, since the size cannot be identified with the naked eye, each color component divided as shown in this figure cannot be visually recognized.

  However, in the second region (14), the transparency of the lowermost base material (6) can be visually recognized through the hollowed portion (9) of the concealing layer (7) as the lower layer under transmitted light. It is necessary to set the transmittance.

  Since the print medium (1) is the base material (6) made of the light transmissive material (5), the portion of the second region (14) in the upper layer of the cutout portion (9) of the concealing layer (7) is As described above, since it is directly affected by the permeability of the base material (6), the color is different from that of the second region (14) in the upper layer of the other 2a concealing part (12). Visible. This state is shown in FIG.

  As shown in FIG. 8D, in the second region (14), the region corresponding to the same portion as the lower cut-out portion (9) changes its color upon receiving transmitted light. A portion that changes color under transmitted light in the second region (14) is defined as a latent image portion (15). The element for forming the first latent image (4), which is a feature of the present invention, is the latent image portion (15). In the second region (14), a region other than the latent image portion (15) is defined as a first camouflage portion (16).

  As described above, in the latent image portion (15), the second region (14) of the uppermost image forming layer (8) is formed on the substrate (6). ) Is formed of the light-transmitting material (5), and in order to make the first latent image (4) visible in the present invention, the transmittance of the substrate (6) is used only under the transmitted light. It is necessary to visually recognize the latent image portion (15). Therefore, under reflected light (diffused light), the first camouflage portion (16) and the latent image portion (15) in the second region (14) must be of the same color.

  Under the reflected light (diffuse light), the latent image portion (15) in the second region (14) and the first camouflage portion (16) become the same color, so that the first latent image (4) is The substrate (6) in the latent image portion (15) has a color difference ΔE with respect to the first camouflage portion (16) that is not visually recognized but is observed through the print medium (1) under transmitted light. The value changes, and the first latent image (4) formed by the latent image portion (15) can be visually recognized.

  Next, the second mode of the image forming layer (8) of the first embodiment will be described with reference to FIG. In the second region (14) described with reference to FIG. 8, the color material forming the latent image portion (15) and the color material forming the camouflage portion (16) are the same color in each color separation region. Although described with reference to the structure formed of the material, the second aspect uses two colors of different color materials for the latent image portion (15) and the camouflage portion (16) in each color separation region. To form. Hereinafter, the configuration will be described in detail.

  FIG. 9A shows the second concealment region (11) of the concealment layer (7) and the second region (14) of the image forming layer (8) among the three layers described in FIG. It is the perspective view which decomposed | disassembled the lamination | stacking state. FIG. 9B and FIG. 9C show a case where each region is viewed from directly above in this state. Note that the second area (14) in FIG. 9B is a state when the print medium (1) is observed in the diffused light area, and the second area (14) is constituted by three color separation areas. Has been. Actually, the color components that are divided as shown in this figure are not visually recognized because they cannot be identified with the naked eye.

  The first region (13) is the same as in the first embodiment, but in the second region (14), the first region (13) is at the same position as the hollow portion (9) formed in the lower concealing layer (7). A so-called latent image portion (15) and another second region (14), that is, a so-called first camouflage portion (16), which are corresponding portions, are formed. Further, a hollow portion (9) of the second concealment region (11) formed in the lower layer of the second region (14) (in particular, the hollow portion (9a), the hollow portion (9b), and the hollow portion (9c)). And the latent image portion (15) formed in the upper layer portion (in particular, the latent image portion (15a), the latent image portion (15b), and the latent image portion (15c)) are in the same position, and the second a concealment portion (12) (especially 12a, 12b and 12c) and the first camouflage part (16) (especially 16a, 16b and 16c) formed in the upper layer part are respectively at the same position.

  Further, as described above, in the latent image portion (15), the uppermost second region (14) is formed on the transparent substrate (6). ) Is formed of a material that transmits light, and in order to make the first latent image (4) of the present invention visible, the latent image using the transparency of the base material (6) is used only under transmitted light. It is necessary to make the image part (15) visible.

  Therefore, under reflected light (diffused light), the first camouflage portion (16) and the latent image portion (15) in the second region (14) must be of the same color. That is, 16a, 16b and 16c in the first camouflage portion and 15a, 15b and 15c in the latent image portion need to be the same color.

  Therefore, the 2a region (14a), the 2b region (14b), and the 2c region (14c) are formed by two colors of the first camouflage portion (16) and the latent image portion (15), respectively. Will be. The latent image portion (15) is formed with a transmittance of 3% to 100%. If it is lower than this range, the transparency of the lowermost substrate (6) cannot be visually recognized.

  The equal (same) color in the present invention indicates that the color difference ΔE is less than 6 when observed in a diffused light region under a visible light source. In general, when the color difference ΔE is around 6, there is a possibility that a different color is visually recognized. However, as described above, in the present invention, the first region (13) and the second region (14) are configured with a minute size that cannot be distinguished and visually recognized by the naked eye. . Therefore, if the color difference ΔE is less than 6, in the diffused light region under the visible light source, the latent image portion (15) and the first camouflage portion (16) in the second region (14) are not visible to the naked eye. Visible as a color.

  Note that due to metamerism, when viewed in a diffused light region under a visible light source, a color visually recognized by the naked eye is viewed in a different color when observed in a diffused light region under a specific light source. Even in this case, in the present invention, the latent image portion (15) and the first camouflage portion (16) in the second region (14) are formed in the same color.

  In addition, since the print medium (1) of the present invention is formed of at least two colors so that the first latent image (4) can be clearly seen, the first latent image (4) is formed. ) Is formed of, for example, three color separation regions (14a, 14b and 14c) based on YMC color components, the first latent image (4) to be formed is formed. As for the color balance and gradation of (), each cutout portion at a position corresponding to the three color separation regions (14a, 14b and 14c) of the image forming layer (8) in the cutout portion (9) of the hiding layer (7). This is possible by changing the size of (9a, 9b and 9c).

  The area (vertical × horizontal) of each region in the halftone dot configuration constituting the image forming layer (8) shown in FIG. 5B is, for example, the first region (13) formed by m × m, When the second region (14) is formed by n × n, it can be set as appropriate within a range of m> n> 0.

  The ink for printing the first region (13) and the second region (14) constituting the image forming layer (8) is cyan (C), magenta (M), yellow (Y) used for general commercial printing. And black (Bk) process basic inks, and special color inks in which one color material is produced using these process inks and special color pigments. Types of ink include offset ink, gravure ink, screen ink, and ink for inkjet printers.

(Observation principle of each image)
The configuration of each layer and the positional relationship in the stacked state have been described. Here, the visual recognition principle of the visible image (3) and the first latent image (4) of the present invention in the configuration and positional relationship of each layer described above. Will be described.

  First, the observation position necessary for visually recognizing the visible image (3) and the first latent image (4) will be described. As described above, the latent image portion (15) and the first camouflage portion (16) in the image forming layer (8) are visually recognized as the same color under reflected light (diffused light) under a visible light source. The latent image portion (15) (actually, the base material (6) visually recognized from the latent image portion (15)) cannot be visually recognized with the naked eye. The latent image portion (15) is configured to be visible. In general, the color of an object is determined by a light source, an observation environment (temperature), a spectral reflectance of the object, and the like. Although the way of visually recognizing colors varies depending on these observation conditions, the observation conditions in the present invention are constant conditions (for example, the observation condition: the light source is D65 and the observation environment is 20 ° C.).

  FIG. 10 shows the visible light source (R) and viewpoint when the print medium (1) according to the present invention is observed with reflected light (diffused light) and transmitted light at an observation position with respect to a visible light source (R) at a fixed position. It is the figure which showed three positional relationships of (E1, E2) and print medium (1). When the visible light source (R), the viewpoint (E1), and the print medium (1) are in the positional relationship shown in FIG. 10A, the observation is made under reflected light (diffused light). When the visible light source (R), the viewpoint (E2), and the print medium (1) are in the positional relationship shown in FIG. 10B, the observation is performed under transmitted light.

  Next, the principle that the color difference ΔE between the latent image portion (15) and the first camouflage portion (16) changes by a predetermined value due to the change in the observation position will be described. As described above, the reflected light (diffused light) in the present invention is a position where the light receiving angle is −10 to 10 ° when the incident light angle from the visible light source (R) at a fixed position is 45 °, The transmitted light is a position where the print medium (1) is placed on a straight line connecting the visible light source (R) at a fixed position and the viewpoint (E2), and the print medium (1) is viewed through the visible light source (R) in a watermarked manner. That is. In the print medium (1), the latent image portion (15) and the first camouflage portion (16) are the same color in the positional relationship meaning the reflected light (diffused light) shown in FIG. The respective regions cannot be distinguished and visually recognized, and only the visible image (3) is visually recognized.

  On the contrary, under the transmitted light shown in FIG. 10B, the latent image portion (15) is formed of the base material (6) using the light transmissive material (5). Thereby, by changing the observation position from the reflected light (diffused light) to the transmitted light with respect to the visible light source (R) at the fixed position, the brightness and / or color changes, and the latent image portion (15) and The color difference ΔE of the first camouflage portion (16) changes by a predetermined value. Therefore, the latent image portion (15) is visible and the first latent image (4) is visible.

  FIG. 11 is a graph showing the color difference ΔE of the latent image portion (15) and the first camouflage portion (16) under reflected light (diffused light) or transmitted light according to the present invention. The left side shows the color difference ΔE between the latent image portion (15) and the first camouflage portion (16) under reflected light (diffused light), and the right side of FIG. 11 shows the latent image portion (15) and the first camouflage portion under transmitted light. The color difference ΔE of one camouflage portion (16) is shown. The halftone dot configuration in FIG. 11 is the same as that in FIG.

  First, the measurement sample is a measurement sample A (4 × 4 cm), and the first region (13) has an area corresponding to 30 × 30 pixels with a resolution of 600 dpi (hereinafter, the same resolution) and a second area. The area (14) has an area corresponding to 12 × 12 pixels, the three color separation areas (14a, 14b, and 14c) based on YMC color components each have an area corresponding to 12 × 4 pixels, and a thickness of 0.2 mm. 100% of the area ratio of the hollowed portion (9) in the second concealing region (11) as the concealing layer (7) on the substrate (6) made of the PET film having 100% (the second concealing region (11) is all The first concealed region (9)) and white ink (Toyo Ink Manufacturing Co., Ltd., LIOJET FV03 White) by inkjet printing. 0) is a hidden area ratio of 100% (solid printing), and the area ratio of the latent image portion (15) is 100% (first printing) without printing the first area (13) as the image forming layer (8). The area ratio of the camouflage part (16) is 0%) and three color separation regions (14a, 14b and 14c) based on YMC color components are processed with process ink (Toyo Ink Manufacturing Co., Ltd., LIOJET FV03 cyan, magenta and yellow). And produced by inkjet printing.

  In addition, the measurement sample B (4 × 4 cm) has a YMC color of the first region (13) with an area corresponding to 30 × 30 pixels and the second region (14) with an area corresponding to 12 × 12 pixels. The three color separation regions (14a, 14b and 14c) due to the components each have an area corresponding to 12 × 4 pixels, and a concealing layer (7) is formed on a substrate (6) made of a PET film having a thickness of 0.2 mm. The area ratio of the cutout portion (9) in the second concealment region (11) is 0% (the second concealment region (11) has no cutout portion (9)), and white ink (Toyo Ink Manufacturing Co., Ltd.) Manufactured by LIOJET FV03 White), the first hiding area (10) and the second hiding area (11) are 100% hiding area (solid printing) by inkjet printing to form an image forming layer (8). The area ratio of the first camouflage part (16) of the second area (14) is set to 100% (the area ratio of the latent image point part (15) is 0%) without printing the first area (13). , Three color separation regions (14a, 14b and 14c) based on YMC color components were produced by inkjet printing using process ink (Toyo Ink Manufacturing Co., Ltd., LIOJET FV03 cyan, magenta, yellow and black).

  The graph showing the color difference ΔE between the latent image portion (15) and the first camouflage portion (16) under reflected light (diffused light) shown in FIG. 11, and the latent image portion (15 under the transmitted light shown in FIG. 11) ) And the first camouflage section (16), the color difference ΔE is measured using a self-recording spectrophotometer (manufactured by HITACHI, model U-4000), and the spectral reflectance and spectral characteristics of the measurement sample A and the measurement sample B with wavelengths of 400 to 700 nm. The transmittance was measured, and the color difference ΔE was calculated from the obtained value. Note that the measurement sample A and the measurement sample B do not print the first region (13) as the image forming layer (8), so the area ratio of the measurement sample A (first camouflage portion (16) is 0%. That is, the color difference ΔE between the latent image portion (15) and the measurement sample B (the first camouflage portion (16) is 100%) is determined as the color difference ΔE. It is expressed as a color difference ΔE from one camouflage portion (16).

  As shown in FIG. 11, under reflected light (diffused light), the color difference ΔE between the latent image portion (15) and the first camouflage portion (16) is a relatively small value of 1.23. ing. As described above, if the color difference ΔE is less than 6, the colors are the same color. Therefore, under the reflected light (diffused light), the latent image portion (15) and the first camouflage portion (16) can be said to be the same color. . Therefore, the latent image portion (15) and the first camouflage portion (16) are difficult to identify with the naked eye, and as a result, the first latent image formed in the transmission latent image region (2). (4) cannot be visually recognized.

  Conversely, under the transmitted light shown in FIG. 11, the color difference ΔE between the latent image portion (15) and the first camouflage portion (16) is 7.37. The color difference ΔE between the latent image portion (15) and the first camouflage portion (16) under reflected light (diffused light) is 1.23, whereas the latent image portion (15) and the first image under the transmitted light are equal to 1.23. The color difference ΔE from the camouflage portion (16) is 7.37. That is, by changing the observation position from below reflected light (diffused light) to below transmitted light, the color difference ΔE changes by 6.14 from 1.23 to 7.37. Therefore, when the color difference ΔE changes by 5 or more, the latent image portion (15) and the first camouflage portion (16) can be identified with the naked eye, and as a result, in the transmission latent image region (2). It is possible to visually recognize the formed first latent image (4).

  Note that reflected light (diffused light) and transmitted light can be switched with respect to the visible light source (R) by changing the observation position. That is, the latent image portion (15) and the first camouflage portion (16) can be identified with the naked eye by seeing the base material (6) through the visible light source (R). As a result, the first latent image (4) formed in the transmission latent image region (2) can be visually recognized.

(Visibility principle of visible image in the present invention)
Furthermore, the principle that the visible image (3) is visually recognized will be described in detail. FIG. 12 is a plan view of the transmission latent image region (2) formed on the print medium (1) according to the present invention when viewed with the naked eye in a diffused light region under a visible light source (R) at a fixed position; It is a partial enlarged schematic diagram. In the transmissive latent image region (2), the first halftone dot portion (13a) is visible in the diffused light region under the visible light source (R) as shown in the partially enlarged view of FIG. On the contrary, since the latent image portion (15) and the first camouflage portion (16) in the image forming layer (8) are visually recognized as the same color, the respective regions cannot be distinguished. Therefore, the first latent image (4) formed by the latent image portion (15) cannot be viewed, and only the visible image (3) shown in FIG.

  FIG. 12C is a schematic diagram illustrating the relationship between the print medium (1), the visible light source (R), and the viewpoint when the visible image (3) is viewed. When the print medium (1) is viewed with the naked eye in the diffused light region under the visible light source (R), first, in the first region (13), incident light (R1) from the visible light source (R). Thus, specularly reflected light (R2) and diffused light (R3) are generated, and diffused light (R3) is obtained in the diffused light region.

  In the second region (14), incident light (R1) from the visible light source (R) generates specularly reflected light (R4) and diffused light (R5). In the diffused light region, diffused light (R5) is generated. can get. Further, since the second region (14) is composed of the latent image portion (15) and the first camouflage portion (16), it reflects and diffuses specularly reflected light (not shown), respectively. Light (not shown) is obtained. The latent image portion (15) and the first camouflage portion (16) are formed so as to have the same color when observed in the diffused light region under the visible light source. Differences are not visible to the naked eye.

  In the halftone dot configuration constituting the image forming layer (8) in the present invention, the area of the first region (13) is configured to be larger than that of the second region (14). Therefore, in the diffused light region under the visible light source, the first region (13) is observed more dominantly than the second region (14). Further, as described above, the latent image portion (15) and the first camouflage portion (16) in the second region (14) are formed so as to have the same color when observed in the diffused light region under the visible light source. Therefore, the first latent image (4) formed by the latent image portion (15) cannot be viewed, and only the visible image (3) can be viewed.

(First viewing principle of latent image in the present invention)
Next, the details of the principle by which the first latent image (4) can be visually recognized will be described. FIG. 13 is a plan view and schematic view when the transmission latent image region (2) formed on the print medium (1) of the present invention is viewed with the naked eye under transmitted light under a visible light source (R) at a fixed position. FIG. The transmitted latent image region (2) is formed under the transmitted light under the visible light source (R) as shown in the partially enlarged view of FIG. 13 (b). The position corresponding to the cut-out portion (9) is visible with the naked eye. That is, the first latent image (4) can be visually recognized.

  This is because the latent image portion (15) and the first camouflage portion (16) in the second region (14), which are indistinguishable in the same color under reflected light (diffused light), are transmitted under the transmitted light. Is transmitted through the substrate (6) which hits the lower part of the latent image portion (15) and the latent image portion (15) of the image forming layer (8) and the The color difference ΔE from one camouflage part (16) changes by a predetermined value, and the latent image part (15) and the first camouflage part (16) are distinguished with the naked eye in the same second region (14). Because it became possible.

  The visual recognition principle of the first latent image (4) under the transmitted light under the visible light source (R) will be described with reference to FIG. When the print medium (1) is viewed with the naked eye under transmitted light under the visible light source (R), first, incident light from the visible light source (R) is applied to the first region (13). Through (R1), transmitted light (R4) is obtained.

  In the latent image portion (15) that forms the first latent image (4), transmitted light (R5) is obtained. In the first camouflage section (16), the transmitted light (R4) is obtained by the incident light (R1) from the visible light source (R).

  Therefore, the latent image portion (15) receives the transmitted light from the base material (6) formed of the light transmissive material (5), and receives the first region (13) and the first camouflage portion (16). Higher than the respective transmitted light (R4), and due to the difference in brightness, a high color difference ΔE is generated in the latent image portion (15) with respect to the first camouflage portion (16), and the first latent image as the transmitted latent image is obtained. The latent image (4) can be visually recognized. Therefore, when the print medium (1) is observed under transmitted light under a visible light source, the first latent image (4) can be newly visually recognized.

(Second Embodiment)
Next, another embodiment of the present invention will be described. The base material (6) and the image forming layer (8) are the same as those in the first embodiment, and are omitted. A part of 7) that is the same as that in the first embodiment will be omitted.

  In the second embodiment, as different from the first embodiment, the hollow portion (9) is not formed in the concealment layer (7), and the area ratio is lower than the concealment portion (12) of the 2a. By forming the second b concealing portion (17), the latent image portion (15) is formed due to the difference in the concealing area ratio and the transmittance.

  First, the layer structure in the masking layer (7) will be described with reference to FIG. Since the concealing layer (7) plays the role of concealing the transparency of the base material (6) as in the first embodiment, the white concealing layer (7) is the same as in the first embodiment and the second embodiment. It is formed using ink. However, white ink is also printed on the portion corresponding to the cutout portion (9) in the first embodiment as shown in FIG. 14 (c), but the first concealment region (10) and the second a The hidden area ratio is lower than the hidden area ratio of the concealing portion (12), and this region is defined as the second concealing portion (17).

  Therefore, the relationship between the first concealment area (10) and the concealment area ratio of the second concealment part (12) and the second concealment part (17) constituting the concealment layer (7) is the first concealment area. Region (10) ≧ 2a concealing part (12)> 2b concealing part (17). However, since the 2b concealing part (17) needs to be accompanied by the transparency of the underlying base material (6) under transmitted light, the concealed area ratio is in the range of 0% to less than 100%. There is a need.

  Moreover, since the 1st concealment area | region (10) and the 2a concealment part (12) need to suppress the transmittance | permeability of the base material (6) of a lower layer under reflected light (diffuse light), about concealment area ratio Needs to be greater than 0% and less than or equal to 100%. As described above, the second b concealment part (17) is defined by dividing it from the cutout part (9) in the first embodiment by printing white ink. The hidden area ratio of (17) may be 0%. For example, as in the first embodiment, the hidden area rate of the first hidden region (10) is 100%, the hidden area rate of the 2a hidden portion (12) is 100%, and the 2b hidden portion (17 ) May be 0%. Note that the first concealment region (10) and the second a are based on the light transmittance of the concealment layer (7) (for example, the light transmittance of the concealment layer (7) formed of white ink and having a concealment area ratio of 100%). Since the appropriate range of the concealment area ratio of the concealment part (12) and the second b concealment part (17) is different, the concealment part (12) is not limited to the proper range described above.

  As described above, the second-b concealment part (17) is made lower in the concealment area ratio than the first concealment region (10) and the second-a concealment part (12). ), The first latent image (4) is formed by arranging a plurality of the second b concealing portions (17). The concealment area ratio of the first concealment region (10), the 2a concealment portion (12), and the 2b concealment portion (17) is set to be close to 0% or 0%, that is, the concealment layer ( 7) Even if the setting is substantially omitted, if the transparency of the 2b concealing portion (17) as the print medium is higher than that of the first region (13) and the second region (14), The first latent image (4) is visible. However, when the concealment area ratios of the first concealment region (10) and the 2a concealment unit (12) and the 2b concealment unit (17) approximate, the first latent image (4) under transmitted light Since visibility may be lowered, it is necessary to appropriately set the concealment area ratio of the first concealment region (10), the 2a concealment unit (12), and the 2b concealment unit (17).

  Since the concealing layer (7) has such a configuration, the second-b concealing portion (17) has a concealed area ratio lower than that of other concealing regions. The strength of the light-shielding layer is larger than that of the other concealment regions, and the region corresponding to the second-b concealment portion (17) of the concealment layer (7) in the second region (14) of the image forming layer (8) is the base material. A latent image portion (15) for forming the first latent image (4) described in the first embodiment is formed by the transmitted light of (6).

(Third embodiment)
Next, another embodiment of the present invention will be described. The three layer configurations of the substrate (6), the concealing layer (7), and the image forming layer (8) are the same as those in the first embodiment and the second embodiment. Since this is the same as that of the embodiment, overlapping portions will be omitted.

  In the first and second embodiments, a visible image (3) visible under reflected light (diffused light) and a first latent image (4) visible under transmitted light are formed. However, in the third embodiment, the second latent image (18) that is visible under an infrared light source is formed.

  The print medium (1) in the third embodiment is the same as FIG. 1 in appearance. However, the formed image is visible under the reflected light (diffused light) described in the first and second embodiments, as shown in FIGS. 15A and 15B. Visible image (3), first latent image (4) visible under transmitted light, and visible under the infrared light source newly added in this embodiment, as shown in FIG. 15 (c) Are the second latent image images (18).

  In order to form the second latent image (18), the image forming layer (8) needs to be configured differently from the first embodiment and the second embodiment. The configuration of 8) will be described. In addition, about a base material (6) and a concealing layer (7), it is the same as that of 1st Embodiment and 2nd Embodiment.

  FIG. 16A shows the transmission latent image region (2) in the image forming layer (8), and FIG. 16B is a partially enlarged view of the halftone dot configuration. As shown in FIG. 16B, the basic halftone dot configuration is the same as that of the first embodiment and the second embodiment described above, and the second region surrounds the first region (13). (14) is arranged without gaps. Here, as a difference from the above-described embodiment, another third region (19) is arranged in the first region (13). However, the third region (19) does not necessarily have to be arranged in the first region (13), but at least two color separations arranged in the second region (14). Similar to the region, it may be arranged in the second region (14). This arrangement example will be described later together with other shape examples of each region.

  FIG. 16C1 is a diagram illustrating an example of the visible image (3) and the first region (13). The first region (13) is a region for forming a visible image (3) that is visible under reflected light (diffused light) under a visible light source. Since the configuration for forming the visible image (3) has already been described, a description thereof will be omitted. However, the second latent image (18) in the present embodiment is visible under an infrared light source, so The point portion (13a) is formed using a colored color material (particularly colored ink) that does not contain an infrared absorbing dye. When the first halftone dot portion (13a) is formed of a colored color material that does not contain an infrared absorbing dye, the visible image (3) is obtained when the first halftone dot portion (13a) is observed using a special identification device such as an infrared camera. It cannot be visually recognized.

  In addition, it does not specifically limit in the colored color material which does not contain an infrared absorption pigment | dye, if it does not have an infrared absorption characteristic, Well-known gravure ink, screen ink, process ink, etc. can be used. For example, among the basic four color inks, general cyan (C), magenta (M), and yellow (Y) have a property of not absorbing infrared rays, and a black system based on subtractive color mixture of these three colors. In other words, the same effect as a pigment that does not absorb infrared rays can be obtained. Further, as black ink having infrared transmission characteristics, chromofine black ink (manufactured by Dainichi Seika Kogyo Co., Ltd.) and dye-based ink for ink jet printer (for example, dye-based black ink manufactured by Canon, etc.) can also be used.

  FIG. 16C2 is a diagram illustrating an example of the first latent image (4) and the second region (14). The second region (14) is a region for forming a first latent image (4) that is visible under transmitted light. Since this configuration is also the same as that of the first embodiment and the second embodiment described above, description thereof will be omitted.

  FIG. 16 (c3) is a diagram illustrating an example of the second latent image (18) and the third region (19). The third region (19) is a region for forming the second latent image (18) visible under the infrared light source shown in FIG. 16 (c3), and the third halftone dot portion (19a). And a second camouflage portion (19b). A plurality of second latent image images (18) are arranged in accordance with the area ratio between the third halftone dot portion (19a) and the second camouflage portion (19b) in the third region (19). It is possible to give gradation by the area (19) of 3. In the third region (19), the third halftone dot portion (19a) is formed using a colored color material containing an infrared absorbing dye.

  In addition, the colored color material containing the infrared absorbing dye includes black (Bk) mainly composed of carbon black. However, it is not limited to this as long as it is a colored color material having infrared absorption characteristics. For example, organic dyes having absorption in the infrared region include compounds such as polymethylene, phthalocyanine, azo, and anthraquinone, and inorganic infrared absorbers include antimony-doped tin oxide and tin-doped indium oxide. It is done.

  In the third region (19), the second camouflage portion (19b) is formed in the same color as the third halftone dot portion (19a) using a colored color material that does not contain an infrared absorbing dye. As described above, the uniform color in the present invention refers to a color that is visually recognized by the naked eye when observed under reflected light (diffused light) under a visible light source. Specifically, the color difference ΔE is 6. Less than color. Note that due to metamerism, when observed under reflected light (diffused light) under a visible light source, the color visually recognized by the naked eye was observed under reflected light (diffused light) under a specific light source. In this case, the second camouflage portion (19b) and the third halftone dot portion (19a) are formed in the same color even when visually recognized in different colors.

  The third halftone dot portion (19a) is formed using a colored color material containing an infrared absorbing dye, and the second camouflage portion (19b) is formed using a colored color material containing no infrared absorbing dye, By forming the same color as the third halftone dot portion (19a), the third halftone dot portion (19a) and the second camouflage portion (19b) are visually recognized as the same color under the visible light source. . Therefore, the third region (19) is in a uniform flat mesh state, and the second latent image (18) cannot be recognized with the naked eye, but is observed using a special appraisal device such as an infrared camera. In this case, the second latent image (18) can be visually recognized.

  The third dot portion (19a) and the second camouflage portion (19b) can be formed in the third region (19) by overlapping or hair removal, but in the present invention, they are formed by overlapping. It is preferable to do. When forming by tapping, high printing accuracy is required. When the printing accuracy is low, a printed portion is generated around the third halftone dot portion (19a). Thereby, the third region (19) does not become a uniform flat net state under a visible light source, and the second latent image (18) may be visible with the naked eye.

  FIG. 17A shows a state in which the transmission latent image region (2) is configured by three layers in the state where the configuration of the image forming layer (8) is used, and Y1 in FIG. -Y2 sectional drawing is FIG.17 (b). As shown in FIG. 17A, the print medium (1) according to the third embodiment has a configuration in which the above-described third region (19) is added to the configuration of the first embodiment described with reference to FIG. It is. In the third embodiment, since the third halftone dot portion (19a) is formed of a color material containing an infrared absorbing dye, the masking layer (7) may not contain an infrared absorbing dye. Necessary. If the masking layer (7) contains an infrared absorbing dye, the second latent image (18) formed by the third halftone dot portion (19a) cannot be viewed under an infrared light source. .

  Further, the hiding layer (7) formed of the hiding material preferably has a transmittance in the infrared region of 80% or less. When the transmittance in the infrared region of the hiding layer (7) is 80% or more, the substrate (6) is removed when the print medium obtained by the third embodiment is observed under an infrared light source. The concealing layer (7) to conceal is transmitted, and the first region (13), the second region (14) and the third region (19) are all transmitted, and the substrate (6) is observed. . Therefore, when the base material (6) contains an infrared absorbing pigment, the concentration is observed to be high (blackish). Therefore, the third halftone dot portion (19a) cannot be distinguished from other regions, and as a result, the second latent image (18) that can be observed under infrared light cannot be viewed. Therefore, it is not preferable that the transmittance in the infrared region of the hiding layer (7) is 80% or more.

  FIG. 18 is a graph showing an example of the spectral transmittance of white ink and magenta ink according to the present invention. (A) in FIG. 18 is the spectral transmittance of the concealment material in the present invention, and is formed into a colorless (transparent) PET film by inkjet printing using white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.) as a measurement sample. A solid-printed one was used. (B) in FIG. 18 is the spectral transmittance of the concealment material in the present invention. The white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.) is used as a measurement sample on the PET film by ink jet printing. The sample shown in a) was printed at a lower print density.

  (C) in FIG. 18 is the spectral transmittance of the color material that does not contain the infrared absorbing dye in the present invention. PET film by inkjet printing using magenta ink (LIOJET FV03 Magenta manufactured by Toyo Ink Manufacturing Co., Ltd.) as a measurement sample. A solid-printed one was used. The spectral transmittance shown in FIG. 18 indicates the spectral transmittance of each measurement sample divided by the spectral transmittance of a colorless (transparent) PET film as a base material. , And measured using a self-recording spectrophotometer (U-4000 model made by HITACHI).

  Comparing changes in spectral transmittance in the infrared region of 760 to 800 nm, the spectral transmittance of the concealing material (a) is substantially constant at about 50% in any region. The spectral transmittance of the concealing material (b) printed at a reduced printing density is about 80% in the infrared region, which is a higher value than the concealing material (a) printed solid. The infrared transmitting material (c) containing no infrared absorbing dye has a high value in the infrared region, about 95%, compared with the white ink (a) printed solid and the white ink (b) printed at a reduced printing density. It has become. In the case of a colorant that does not contain an infrared absorbing dye at the same wavelength, the lower spectral transmittance is visually recognized as having a higher density (whiter), and conversely, the higher spectral transmittance has a lower density ( Visible visually. When observed with an infrared camera, the concealing material (a) is white, the concealing material (b) printed at a reduced printing density is pale white, and the infrared transmitting material (c) is substantially transparent. Observed.

  In the second region (14), the first camouflage part (16) is the same color as the latent image part (15) under reflected light (diffused light) under a visible light source, and the first camouflage part (16 ) Or a colored color material containing or not containing an infrared absorbing dye. As described above, the first camouflage portion (16) is formed by partially exposing the light transmissive material (5) as the base material (6) through the hollow portion (9) to which no concealing material is applied. Has been. For this reason, when the base material (6) contains an infrared absorbing dye, the first camouflage portion (16) needs to be formed of a colored coloring material containing the infrared absorbing dye. When the infrared absorbing dye is not included, the first camouflage portion (16) needs to be formed of a colored color material that does not include the infrared absorbing dye. This is because the visibility of the second latent image (18) is affected when the second latent image (18) is observed with a device such as an infrared camera.

  The second latent image when the substrate (6) contains and does not contain an infrared absorbing dye, and when the colored color material forming the first camouflage portion (16) contains and does not contain an infrared absorbing dye. The difference between the observed images of the image (18) will be described later.

The area (vertical × horizontal) of each region in the halftone dot configuration of the third embodiment is formed such that the first region (13) is m × m and the second region (14) is n × n. If the third region (19) is formed by k × k, it can be set as appropriate within the range of m>n> 0 and m>k> 0. Preferably, the first region (13) is m × m (m ≧ 2, m is an integer), the third region (19) is k × k (k ≧ 1, k is an integer), the second region ( 14) is formed by n × n (n ≧ 1, n is an integer), and the area of the first region (13) is the sum of the areas of the second region (14) and the third region (19). Greater than (m ² > n ² + k ² ). When the area of the first region (13) is smaller than the sum of the areas of the second region (14) and the third region (19), observation is performed under reflected light (diffused light) under a visible light source. In this case, the second region (14) and the third region (19) become noise, which is not preferable because the visibility of the visible image (3) is lowered.

  FIG. 19 shows an example of the spectral reflectance of the transparent base material (6) according to the present invention, the hiding material for forming the hiding layer (7), the ink not containing the infrared absorbing dye, and the ink containing the infrared absorbing dye. It is a graph. (A) in FIG. 19 shows the spectral reflectance of the substrate (6) in the present invention, and a colorless (transparent) PET film having a thickness of 0.2 mm not containing an infrared absorbing dye was used as a measurement sample. . (B) in FIG. 19 is the spectral reflectance of the concealing layer (7) in the present invention, and the PET film described above by inkjet printing using white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.) as a measurement sample. A solid-printed one was used. (C) in FIG. 19 is the spectral reflectance of the color material that does not contain the infrared absorbing dye in the present invention. PET film by inkjet printing using magenta ink (LIOJET FV03 magenta manufactured by Toyo Ink Manufacturing Co., Ltd.) as a measurement sample. A solid-printed one was used. (D) in FIG. 19 is a spectral reflectance of the color material containing the infrared absorbing pigment in the present invention, and a black ink (LIOJET FV03 Black manufactured by Toyo Ink Manufacturing Co., Ltd.) is used as a measurement sample on a PET film by inkjet printing. A solid-printed one was used.

  The spectral reflectance shown in FIG. 19 was measured using a self-recording spectrophotometer (manufactured by HITACHI, model U-4000).

  Comparing changes in spectral reflectance in the visible light region of 400 to 760 nm and the infrared region of 760 to 800 nm, the spectral reflectance in the PET film (a) is substantially constant at around 95% in any region. is there. The spectral reflectance of the white ink (b) is substantially the same as that of the PET film (a) in both the visible light region and the infrared region, except for the short wavelength in the visible light region. Further, the spectral reflectance of the magenta ink (c) is substantially constant at around 95% in the infrared region. The spectral reflectance of the black ink (d) is substantially constant at around 5% in the infrared region. At the same wavelength, the higher the spectral reflectance, the lower the density is visually recognized (whiter), and the lower the spectral reflectance, the higher the density (blackish) is visually recognized. When observed using an infrared camera, the PET film (a) and the magenta ink (c) were observed to be whitish (substantially transparent), the white ink (b) was white, and the black ink (d) was observed to be black. .

(The principle of visual recognition of the second latent image)
FIG. 20 shows a state where the transmission latent image region (2) of the print medium (1) formed by the halftone dot configuration of the third embodiment related to the present invention is observed through an infrared display device (hereinafter referred to as “under infrared light source”). 2) is a plan view and a schematic view to be observed. The observation principle of the second latent image (18) under the infrared light source will be described with reference to FIG. As shown in FIG. 20B, when the transmission latent image region (2) is observed under an infrared light source, the concealing layer (7), which is the lower layer of the image forming layer (8), is configured using white ink. Therefore, it is observed white as described above. Moreover, since the 1st area | region (13) is comprised using the colored coloring material which does not contain an infrared absorption pigment | dye, it is observed white.

  When the latent image portion (15) is formed using a colored color material that does not contain an infrared absorbing dye, the base material (6) is formed via the cutout portion (9) of the concealing layer (7) as the lower layer. Observed, when the substrate (6) contains an infrared absorbing dye, it is observed to be slightly black. Similarly, when the latent image portion (15) is formed using a colored color material containing an infrared absorbing dye, it is observed as black. Therefore, the first camouflage portion (16) needs to have a density comparable to that of the latent image portion (15) when observed under an infrared light source, and a colored color material appropriately containing an infrared absorbing dye. It will be formed using. In this case, when observed in the infrared region, the first camouflage portion (16) is observed to be slightly black.

  That is, the latent image portion (15) and the first camouflage portion (16) are observed slightly blackish in the infrared region. Therefore, the second region (14) is observed as a solid region (20) having a uniform concentration, as shown in FIGS. 20 (a) and 20 (b). That is, the first latent image (4) composed of the latent image portion (15) is not observed. Further, the third halftone dot portion (19a) is formed of a colored color material containing an infrared absorbing dye, and is observed in black in the infrared region as described above. On the other hand, the second camouflage portion (19b) is formed of a colored color material that does not contain an infrared absorbing dye, and is observed whitish in the infrared region as described above. Therefore, when the print medium (1) is observed under an infrared light source, the third halftone dot portion (19a) uses the solid region (20) having a uniform density formed by the second region (14) as a background. The constructed second latent image (18) can be observed.

  As described above, under the infrared light source, when the light-transmitting material (5) containing an infrared-absorbing dye is used for the base material (6), the solid region (20) can also be observed. The second latent image (18) refers only to an image formed by the third region (19).

  The case where the base material (6) is observed to be slightly black in the infrared region and the case where the latent image portion (15) is formed using a colored color material containing an infrared absorbing dye will be described with reference to FIG. However, next, the base material (6) does not contain an infrared absorbing dye, has a high spectral reflectance in the infrared region (90% or more), and the latent image portion (15) does not contain an infrared absorbing dye. The case where it is formed by using FIG. 21 will be described with reference to FIG.

  FIG. 21 is a plan view and a schematic view when the transmission latent image region (2) of the print medium (1) formed by the halftone dot configuration of the third embodiment according to the present invention is observed under an infrared light source. . The principle that enables the second latent image (18) to be observed under an infrared light source will be described with reference to FIG. As shown in FIG. 21A, when the transmission latent image region (2) is observed under an infrared light source, the concealing layer (7), which is the lower layer of the image forming layer (8), is configured using white ink. Therefore, it is observed white as described above. Moreover, since the 1st area | region (13) is comprised using the colored coloring material which does not contain an infrared absorption pigment | dye, it is observed white.

  The latent image portion (15) is formed using a colored coloring material that does not contain an infrared absorbing dye, and the base material (6) also does not contain an infrared absorbing dye, and has a high spectral reflectance in the infrared region (90%). From the above, it is observed whitish in the infrared region. Accordingly, the first camouflage portion (16) needs to be formed using a colored color material that does not contain an infrared absorbing dye, and is observed whitish when observed in the infrared region.

  That is, the latent image portion (15) and the first camouflage portion (16) are observed whitish in the infrared region. Therefore, as shown in FIG. 21A and FIG. 21B, the solid region (20) is not observed in the second region (14), but is observed as a uniform white image. That is, the first latent image (4) composed of the latent image portion (15) is not observed. Further, the third halftone dot portion (19a) is formed of a colored color material containing an infrared absorbing dye, and is observed in black in the infrared region as described above. On the other hand, the second camouflage portion (19b) is formed of a colored color material that does not contain an infrared absorbing dye, and is observed whitish in the infrared region as described above. Therefore, when the print medium (1) is observed under an infrared light source, the second latent image (18) composed of the third halftone dot portion (19a) can be observed.

  The visible image (3) formed by the first region (13) of the image forming layer (8) of the present invention, the first latent image (4) formed by the latent image portion (15), and the third halftone dot The second latent image (18) formed by the part (19a) can be appropriately set with letters, numbers, symbols, patterns, landscapes, etc., but for the first latent image (4) In the case of letters, numbers, symbols, and patterns, it is preferable to form a positive image, and in the case of a person or landscape, it is preferable to form a negative image. In the above description, the hollowed portions (9a, 9b, and 9c) and the second-a concealing portions (12a, 12b, and 12c) use a quadrilateral shape, but the shape is not limited to a quadrangular shape. , A triangular shape such as a triangle, a square, and a polygon, a random shape, or a halftone dot shape disclosed in Japanese Patent No. 3478474 filed by the present applicant may be used.

  Further, the shapes of the first region (13), the second region (14) and the third region (19) formed by the image forming layer (8) of the present invention are all rectangular in the above description. However, the present invention is not limited to a quadrangle, and the first region (13), the second region (14), and the third region (19) may be polygonal. For example, in FIG. 22, as an example of another polygon, the first region (13) is a hexagon, and the second region (14) and the third region (19) are triangles.

  In the shape example shown in FIG. 22, each region is triangular, and as described above, the third region (19) is not in the first region (13), but the second region. In the area (14), it is arranged in the same shape as the color separation area. Thus, the third region (19) is not limited to being disposed in the first region (13), and may be disposed in the second region (14). In addition, when arrange | positioning the 3rd area | region (19) in a 2nd area | region (14), it arrange | positions so that it may not overlap with a color separation area | region.

  In the above description, the original image of the first latent image (4) is color-separated into the respective color components of YMC, but R (red), G (green), and B (blue) in the RGB color mode. The second region (14) may be divided into three, and each of the RGB regions may be composed of YMC process ink or special color ink corresponding to RGB. Similarly, the original image of the first latent image (4) may be color-separated with two colors, and the second region (14) may be configured with two colors of special color inks.

  As a method for forming the substrate (6), the concealing layer (7) and the image forming layer (8), respectively, an offset printing method, a gravure printing method, a screen printing method, a flexographic printing method, an inkjet printer, a laser printer, etc. It is not limited.

  Hereinafter, the print medium (1) having a transmission latent image according to the present invention will be described in detail using examples. However, the present invention is not limited to the following examples, and the technology described in the claims. Needless to say, changes can be made as appropriate within a proper category.

  As Example 1, as shown in FIG. 1, a certificate (hereinafter referred to as “certificate”) (1), which is a card-type print medium in which a transmission latent image region (2) according to the present invention is formed in the lower left portion. Produced. When this certificate (1) is observed under reflected light (diffused light) under a visible light source, the transmission latent image area (2) is visually recognized as the “NPB” of the Gothic body shown in FIG. When the book (1) is viewed through the transmitted light under the transmitted light, the “NPB” in the Mincho style shown in FIG. 2B is visually recognized as a full color image in the transmitted latent image area (2).

  As the base material (6) of the certificate (1) in Example 1, a colorless (transparent) PET film having a thickness of 0.2 mm was used. Therefore, in Example 1, the entire surface of the base material was used, that is, the light transmissive material (5) was used for the base material itself.

  Next, the area other than the area corresponding to the transmission latent image area (2) on the substrate (6) is solid-printed using white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.), and the transmission latent image area (2) is The second concealing portion (12) excluding the first concealing region (10) for suppressing the permeability of the PET film of the base material (6) and the hollowed portion (9) in the above-described embodiment is the same white. A masking layer (7) was formed using ink.

  In addition, the 2a concealment part (12) excluding the first concealment area (10) and the cut-out part (9) was printed at a concealment area ratio of 100% (solid). The cut-out portion (9) corresponds to a portion corresponding to YMC that is the three color components constituting the second region (14) in the image forming layer (8) formed on the concealing layer (7). As shown in the figure, it consists of a cutout portion (9a), a cutout portion (9b), and a cutout portion (9c).

  Next, an image forming layer (8) was formed on the entire surface of the concealing layer (7) formed of white ink using process ink (LIOJET FV03 cyan, magenta, yellow and black, manufactured by Toyo Ink Manufacturing Co., Ltd.). . This second region (14) is a color separation region divided by the three color components of YMC, and in the concealing layer (7) below this second region (14), as described above, The cutout portion (9) where the white ink is not printed is arranged, but it is visually recognized that the cutout portion (9) is formed under the second region (14) under reflected light. I can't.

  The second region (14) in the image forming layer (8) at a position corresponding to the hollowed portion (9) of the concealing layer (7) becomes a latent image portion (15) and is a transparent base under transmitted light. The first latent image (4) is formed under the influence of the transmitted light of the material (6).

  In order to prevent the first latent image (4) formed by the latent image portion (15) from being viewed under reflected light (diffused light), other than the latent image portion (15) in the second region (14). The first camouflage portion (16), which is a region, was formed so as to be the same color as the latent image portion (15) under reflected light (diffused light). The color difference ΔE between the first camouflage portion (16) and the latent image portion (15) in the reflected light (diffused light) region (for example, a light receiving angle of 0 °) was 1.14.

  At least the halftone dot configuration of the transmission latent image region (2) of the image forming layer (8) is such that the first region (13) has an area corresponding to 30 × 30 pixels and the second region (14) has 12 ×. An area corresponding to 12 pixels was formed. Moreover, the 1st area | region (13) formed the 1st halftone dot part (13a) by the circular dot.

  By adopting such a positional relationship between the layer configuration and the halftone dot configuration, it is possible to visually recognize the transparency of the base material (6) through the cutout portion (9) in the latent image portion (15). Further, in the areas other than the transmission latent image area (2), since the transparency of the base material (6) is suppressed by the white ink, the process ink printed on the white ink in a state of no transparency. As a result, a visible image (3) is formed.

  When the certificate (1) produced in Example 1 is observed under reflected light (diffused light), the visible image (3) is visually recognized and the first latent image (4) is visually recognized. could not. Next, when the certificate (1) produced in Example 1 was observed under transmitted light, the latent image portion (15) was visually recognized as bright, and the first camouflage portion (16) was observed as dark. Thus, the first latent image (4) could be visually recognized.

  As Example 2, as shown in FIG. 23, a card-type certificate (1 ′) having a transmission latent image region (2 ′) according to the present invention formed in the lower right portion was produced. When this certificate (1 ′) is observed under reflected light (diffused light) under a visible light source, the transmission latent image area (2 ′) is visually recognized as “plural stars” shown in FIG. When the certificate (1 ′) is viewed with respect to the light source under the transmitted light, the transmitted latent image area (2 ′) is visually recognized as “pass” as shown in FIG. When the image is observed, a “smile” image as shown in FIG. 24C can be visually recognized.

  As the base material (6 ′) of the certificate (1 ′) in Example 2, a colorless (transparent) PET film having a thickness of 0.2 mm was used. Therefore, in Example 2, the entire surface of the base material, that is, the light transmissive material (5) was used for the base material itself.

  Next, the area other than the area corresponding to the transmission latent image area (2 ′) on the substrate (6 ′) is solid-printed using white ink (LIOJET FV03 White manufactured by Toyo Ink Manufacturing Co., Ltd.), and the transmission latent image area (2 ') Using the same white ink, the first concealment region (10') and the 2a concealment portion (12 ') for suppressing the transparency of the PET film of the substrate (6') (described later) Furthermore, the permeability of the base material (6 ′) can be visually recognized at a location adjacent to the 2a concealing portion (12 ′) (a position corresponding to the cut-out portion (9) in Example 1). The concealing layer (7 ′) was formed so as to have the 2b concealing portion (17 ′) having the concealing area ratio.

  The first concealment area (10 ′) and the 2a concealment part (12 ′) were printed with a concealment area ratio of 100%, and the second concealment part (17 ′) was printed with a concealment area ratio of 10%. Further, the second-a concealing part (12 ') and the second-b concealing part (17') equally distribute the second region (14 ') of the image forming layer (8') to be printed on the white ink. It has a positional relationship corresponding to the three color components of YMC divided and configured.

  Next, an image forming layer (8 ′) is formed on the entire surface of the concealing layer (7 ′) formed of white ink using process ink (LIOJET FV03 cyan, magenta, yellow and black manufactured by Toyo Ink Manufacturing Co., Ltd.). Formed. About this image forming layer (8 '), normal printing by a halftone dot is performed except for the transmission latent image region (2'), and the transmission latent image region (2 ') is the configuration in the second embodiment described above. It was.

  Note that at least the halftone dot configuration of the transmission latent image region (2 ′) of the image forming layer (8 ′) is such that the first region (13 ′) has an area equivalent to 30 × 30 pixels and the second region (14 ′). ) With an area corresponding to 12 × 12 pixels and the third region (19 ′) with an area corresponding to 9 × 9 pixels.

  In the first region (13 ′), the first halftone dot portion (13a ′) was a circular dot, and was printed using process ink (LIOJET FV03 cyan, magenta and yellow manufactured by Toyo Ink Manufacturing Co., Ltd.). A visible image (3 ′) was formed by changing the area ratio between the first halftone dot portion (13a ′) and the region other than the first halftone dot portion (13a ′).

  As described above, the second region (14 ′) was equally divided by the color materials of the three color components of YMC. Under the second region (14 ′), the second concealment region (11 ′) for concealing the permeability of the base material (6 ′) and the permeability of the base material (6 ′) are visible. A second-b concealment portion (17 ′) having a concealment rate of a certain degree is formed. The second region (14 ′) at the position corresponding to the second b concealing portion (17 ′) forms the first latent image (4 ′) as a latent image portion (15 ′).

  In order not to make the first latent image (4 ′) formed by the latent image portion (15 ′) visible under reflected light (diffused light), the latent image portion (15 ′ in the second region (14 ′)). The first camouflage portion (16 ') other than') was printed so as to be the same color as the latent image portion (15 ') under reflected light (diffused light). The area ratio of the 2a concealing part (12 ') and the 2b concealing part (17') in the concealing layer (7 ') was changed to form a first latent image (4'). The color difference ΔE between the latent image portion (15 ′) and the first camouflage portion (16 ′) under reflected light (diffused light) was 0.65.

  In the 3rd field (19 '), the 3rd halftone dot part (19a') was a circle dot, and it printed using black ink (Toyo Ink Manufacturing Co., Ltd. LIOJET FV03 black). The second camouflage portion (19b ′) was printed in black by superimposing process inks (LIOJET FV03 cyan, magenta and yellow, manufactured by Toyo Ink Manufacturing Co., Ltd.). The area ratio of the third halftone dot portion (19a ′) and the second camouflage portion (19b ′) was changed to form a second latent image (18 ′).

  FIG. 25 schematically shows the configuration of the transmission latent image region (2 ′) and the configuration of the region other than the transmission latent image region (2 ′) in the certificate (1 ′) of the second embodiment. . FIG. 25 (a) shows the configuration of the region other than the transmission latent image region (2 ′), and a white (transparent) PET film substrate (6 ′) having a thickness of 0.2 mm is white. Ink is printed thereon, and further, a halftone dot for forming a visible image (3 ′) is printed thereon by process ink.

  FIG. 25B shows a configuration of the transmission latent image region (2 ′). On the transparent base material (6 ′), the first concealment region (10 ′) and the second concealment portion ( 12 ') and the second b concealment part 17' are printed with white ink, and the first area 13 'is printed on the first concealment area 10' and the second a concealment is performed. The second area (14 ') is printed on the part (12') and the second b concealing part (17 '), and the third area (19') is formed in the first area (13 '). Printed.

  By adopting such a positional relationship between the layer configuration and the halftone dot configuration, in the second region (14 ′), the transmission of the transparent base material (6 ′) through the second b concealing portion (17 ′). The first latent image (4 ′) formed by the latent image portion (15 ′) when the color difference ΔE between the latent image portion (15 ′) receiving the light and the first camouflage portion (16 ′) changes. Can be visually recognized. In addition, the area other than the second b concealing portion (17 ′) is printed on the white ink in a non-transparent state because the transparency of the base material (6 ′) is suppressed by the white ink. A visible image (3 ′) is formed by the process ink.

  When the certificate (1 ′) produced in Example 2 was observed with the naked eye under reflected light (diffused light) under a visible light source with a visible light source at a fixed position, a “plurality of stars” in the visible image (3 ′) was observed. ”Was visually recognized, and the first latent image (4 ′) and the second latent image (18 ′) could not be visually recognized. Next, when the certificate (1 ′) produced in Example 2 was watermarked and observed with the naked eye under transmitted light, the letter “pass” in the first latent image (4 ′) was visually recognized as a full-color image. We were able to. At this time, the visible image (3 ′) and the second latent image (18 ′) could not be visually recognized.

  Furthermore, the certificate (1 ′) produced in Example 2 was used as an infrared display device (Watec Co., Ltd., CCD camera WAT-704R equipped with Fuji Photo Film Co., Ltd., Sharp Cut Filter IR-80). The visible image (3 ′) and the first latent image (4 ′) could not be observed through the observation, but the second image composed of the third halftone dot portion (19a ′). The latent image (18 ′) was dark (blackish) and the “smile” of the second latent image (18 ′) was clearly visible.

DESCRIPTION OF SYMBOLS 1 Print medium which has a transmission latent image 2 Transmission latent image area | region 3 Visible image 4 1st latent image 5 Light transmissive material 6 Base material 7 Hiding layer 8 Image forming layer 9 Hollow part 10 1st hiding area 11 1st 2nd concealment area 12 2a concealment part 13 1st area 13a 1st halftone dot part 14 2nd area | region 15 Latent image part 16 1st camouflage part 17 2b concealment part 18 2nd latent image image 19 3rd area | region 19a 3rd halftone dot part 19b 2nd camouflage part 20 Solid area | region

Claims (7)

In a substrate made of a light-transmitting material that is at least partially colorless and / or colored, a transmission latent image region is formed on a part of the substrate made of the light-transmitting material,
In the transmission latent image region on the base material, a concealing layer made of a concealing material for suppressing the transmissivity of the light transmissive material, and an image formation formed on the concealment layer by a colored color material A layer is formed,
The concealing layer comprises a first concealing region and a second concealing region that conceal the transparency of the substrate,
The second concealment region includes a 2a concealing portion to which the concealing material is applied and a hollow portion without the concealing material, or a 2a concealing portion and the second b to which the concealing material is applied. Concealed part of
The relationship between the concealment area ratios of the first concealment region, the 2a concealment unit, and the 2b concealment unit is as follows: first concealment region ≧ 2a concealment unit> 2b concealment unit,
A plurality of the image forming layers are arranged such that at least the first region and the second region are adjacent to each other,
The first region has a first halftone dot portion that forms a visible image with the colored material.
The second region is divided into at least two color separation regions by different color materials, and is stacked at the same position as the second concealment region, so that the second region is It is divided into a latent image portion that hits the same position as the cutout portion or the second b concealing portion and a first camouflage portion that hits the same position as the second a concealing portion, and a plurality of the latent image portions are arranged. A latent image is formed,
In the second region, the latent image portion and the first camouflage portion are formed so as to have the same color under reflected light (diffused light), so that the visible image is reflected under reflected light (diffused light). The first latent image formed by the latent image portion is visually observed and the color difference ΔE between the latent image portion and the first camouflage portion changes by a predetermined value by observing the base material under transmitted light. A print medium having a transmission latent image, wherein the image is visible. 2. The printing medium having a transmission latent image according to claim 1, wherein the latent image portion is formed with a light transmittance of 3% to 100%. The at least two color separation regions are formed in different colors by using colored materials of cyan, magenta, yellow, black, or a special color for each color separation region. 3. A print medium having the transmission latent image image according to 2. The second area is divided into three color separation areas, and each of the color separation areas is formed of colored materials of cyan, magenta, and yellow, or the second area is divided into four color separation areas. 4. The print medium having a transmission latent image according to claim 3, wherein each of the color separation areas is divided and formed of colored materials of cyan, magenta, yellow and black. By varying the size of the plurality of the cutout portions or the second b concealing portions, the size of the latent image portion is also proportionally different, and the first latent image is a gradation image. A printing medium having a transmission latent image according to any one of claims 1 to 4. 6. The print medium having a transmission latent image according to claim 5, wherein the cutout portion having the different size or the second b concealment portion is formed corresponding to the at least two color separation regions. A third region comprising a third halftone dot portion and a second camouflage portion formed so as to surround the third halftone dot portion is formed in the first region or the second region. ,
The third halftone dot portion is formed of a colored color material containing an infrared absorbing dye to form a second latent image.
The second camouflage portion is formed of a color material that is the same color as the third halftone dot portion under a visible light source and does not contain an infrared absorbing dye,
7. The second latent image is further visible when the transmission latent image region is observed under an infrared light source because at least the first region does not contain an infrared absorbing dye. A printing medium having the transmission latent image according to any one of the above.

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